#include<bits/stdc++.h>
#define int long long
#define INF (0x3f3f3f3f3f3f3f3f)
using namespace std;


signed main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int n;
    double i;
    cin>>n>>i;
    double sum=0;
    for (int a=0;a<=n;a++)
    {
        double x;
        cin>>x;
        sum+=x*pow((1+i),-a);
    }
    cout<<sum;
}